A247717 Numbers n such that A033493(n)/A008908(n) is an integer.

1, 5, 18, 58, 99, 153, 176, 228, 238, 240, 282, 341, 345, 421, 475, 585, 629, 712, 739, 779, 802, 815, 974, 995, 1078, 1088, 1237, 1257, 1262, 1290, 1346, 1398, 1424, 1459, 1673, 1694, 1724, 1731, 1802, 1811, 1916, 1928, 1988, 2170, 2222, 2260, 2272, 2275, 2317, 2365, 2397, 2410

Offset: 1

Author

Derek Orr, Sep 22 2014

Keywords

• nonn

Comments

Equivalently, these are also numbers n such that the average of the numbers in the Collatz (3x+1) iteration of n is an integer.

Crossrefs

Cf. A008908, A033493.

Programs

PARI

Tavg(n)=c=0;s=n;while(n!=1,if(n==Mod(0,2),n=n/2;c++;s+=n);if(n==Mod(1,2)&&n!=1,n=3*n+1;s+=n;c++));s/(c+1)
n=1;while(n<10^4,if(floor(Tavg(n))==Tavg(n),print1(n,", "));n++)